Abstract: Ramsar, a coastal city in the northern part of Iran, has one of the highest levels of natural radiation known to exist in an inhabited area. The study of the effects of high natural background radiation on human health was the main goal of this investigation. We also compared some features in relation with the health between residents of high and normal natural background radiation areas in Ramsar. These preliminary results showed a lack of ill effects among the population in the high background radiation area. These results may indicate that the risk from the high levels of natural background radiation may be less than the predictions of the LNT model of radiation dose response.